Over the years many types of touch pads such as touch screens have been developed for use with processors as user input components. These pads were initially used with major display units, but most recently they are dominant input devices for lap top and hand held computers, notepads and communications devices.
The touch pads may have discrete key locations such as keypad elastomers laid over printed circuit boards or touch screens such as analog resistive, infrared, accoustic, capacitive or electromagnetic inductive operated screens. These touch pads have a common problem in that they do not always provide the user with a satisfactory tactile feedback. The completion of a keystroke on a keypad can usually be seen on the user's screen, but cannot be felt. In addition, touch screens are flat, they do not have any curvature, and therefore no feedback or key travel occurs during a keystroke. This is particularly true for the analog resistive, infrared, accoustic and capacitive screens that are capable of finger as well as pen input. The electromagnetic inductive screen is only capable of a pen input, since the pen picks up a signal from a sensor plate.
Users are uncomfortable when using such devices in that they do not sense having completed a keystroke. Providing some form of tactile feedback when the pad is touched to input a certain key function is essential for good man-machine interface. Prior art devices presently use sound to provide feedback to the user. The feedback is normally in the form of a beep or click, as exemplified in the Philips Velo 1 handheld PC. This feature is noted in the Velo 1 User's Guide on page 31--Adjusting volume and sounds, and in particular the Key Clicks. The Guide which is identified as publication number 000-46365; V1UG197V1 was published in 1998.